Water Extraction System for Dwellings

ABSTRACT

Apparatus ( 10 ) for extracting water from the atmosphere and supplying the extracted water to a domestic water supply to the dwelling, said apparatus being dimensioned and arranged relative to an access opening that leads from the dwelling into a roof space to be small enough to pass through the opening and be located in the roof space, said apparatus further comprising an air intake ( 12 ) located to receive humid air from outside the dwelling, a water extractor having a fan ( 13 ) operable to draw air in through the air intake ( 12 ) and pass the air over a cooling means for condensing water out of the air and means—for collecting the condensed water and supplying the collected water to the water supply tank ( 30 ) of the dwelling to replenish water in the tank. ( 30 )

The present invention relates to extraction and storing of water from atmospheric air for domestic use in dwellings. In particular, although not exclusively, the present invention relates to a water extraction system that can be retrofitted to an existing dwelling house.

There is a need in many developed countries to conserve potable water supplies particularly in times of drought or long dry spells of hot weather. By potable water supplies is meant water that has been treated to make it drinkable.

In the United Kingdom many of the water reservoirs supplying domestic and commercial properties are less capable of coping with the increasing demands during long spells of hot weather, and the levels of water in the reservoirs are running very low. When this happens the water supply authorities often impose restrictions on the use of potable water for non essential uses such as use of hose pipes, washing cars, watering gardens, and other non human consumption purposes.

Water vapour is in abundant supply in atmospheric air. At any given time, it is estimated that earth's atmosphere contains approximately 3.4 quadrillion gallons (or 3.4 trillion US gallons) of water as vapour. This may sound a lot but compared to the world's total watershed it represents approximately 0.001%. The key is that the water in the atmosphere regenerates as a form of recycling of the earth's oceans and fresh ground water. Therefore, so long as there is water on earth, there will be water in the atmosphere. We do not need to be concerned with the quality or type of ground water sources that are evaporating, because only H₂O molecules end up as vapour. However, currently little is done to extract the water from air to supplement the water supplies to individual dwellings such as dwelling houses.

There is a need for a water extraction system that is cheap and easy to install in dwelling houses that can supplement the supply of water to individual dwelling houses.

Prior known water extraction systems for large commercial properties such as office blocks, hospitals schools and the like have been proposed in the past, but in the main these are very expensive and are very large industrial plants that would be impossible to install in the average size dwelling and would certainly be beyond the average “do it yourself” person to retrofit to an existing dwelling. A typical example is shown in U.S. Pat. No. 6,499,309 which comprises a water extractor mounted on the roof of a building but this is incapable of being adapted for installation inside the roof space of a house or other dwelling without a major rebuild of the house.

An object of the present invention is to provide a water extraction system for supplementing domestic water supplies to dwellings that is relatively easy and cheap to install and can be retrofitted to existing dwellings by insertion through a conventional access opening in the ceiling of the dwelling.

A further object of the present invention is to provide such a water extraction system that can be retro-fitted to a dwelling house. An advantage of this is that it minimizes the necessary expenditure for a user with an existing house.

According to one aspect of the present invention there is provided a water extractor system for a domestic water supply for extracting water from the atmosphere and supplementing the domestic water supply to a dwelling, the apparatus comprising an air intake located to receive humid air from outside the dwelling, a water extractor having a fan operable to draw air in through the air intake and pass the air over a cooling means for condensing water out of the air, and means for collecting the extracted water and supplying the collected water to the water supply tank of the dwelling to replenish water in the tank.

Preferably, the water extractor is located in the roof space of the dwelling and the air intake is connected to a ventilated tile of the roof. The ventilated roof tile may be a ventilated ridge tile of the roof. The ventilated roof tile may be connected to the air intake of the water extractor by means of a pipe connector. The water extractor may be located in the roof space of the dwelling and the air intake is a cowling that points into the wind. The air cowling may be one that is rotatable to point into the wind. Rotation of the cowling may be effected by means of an electric motor controlled by a wind direction sensitive monitor.

Preferably the cooling means is a dehumidifier of the type that uses a refrigerant, a compressor to compress the refrigerant and an evaporative cooler to cool the air flowing in contact with the cooler to below its dew point, and thereby condense water from the air.

The cooling means may be a dehumidifier of the type that uses a thermoelectric Peltier cooling device that cools a heat sink that is used to cool the air that contacts the heat sink to below its dew point to condense water from the air.

The fan of the water extractor may be driven by an electrically powered motor, or by a driven by a wind driven turbine.

The water extractor may have a water collection chamber and a pump for pumping condensed water from the collection chamber to a water tank located the roof space of the dwelling,

Preferably a level detector is provided in the chamber that is operable to control the operation of the water extractor so that the water extractor only runs when the tank needs to be topped up.

The air intake may have an air filter to remove air-borne particles in the air. In this case the air filter may be an electrostatic filter.

An ultraviolet light source may be provided for irradiating the condensed water to purify the water. A filtration system may be provided through which the condensed water flows. The filtration system may include a sediment screen for filtering the condensed water. The filtration system may include porous carbon blocks through which the water flows. The condensed water may be subjected to an ozone treatment to produce drinkable water that is available for occupants of the dwelling.

The present invention will now be described by way of examples with reference to the accompanying drawings in which:

FIGS. 1 to 3 show three embodiments of an apparatus constructed in accordance with the present invention for extracting water from the atmosphere and supplementing the domestic water supply to a dwelling;

FIGS. 4 to 6 illustrate different air intakes for use with the present invention.

Referring to FIG. 1 there is shown a water extraction apparatus 10 that can be retrofitted to an existing dwelling such as a house, bungalow, or small domestic industrial unit. Preferably the apparatus 10 is constructed so as to be small enough to pass through the normal access opening that leads from the dwelling into a roof space 9 (This opening is typically 514 mm×514 mm or 514 mm×704 mm) and is located where it can draw in ambient humid air through a suitable air intake 12 and direct the air to a water extractor 14. Preferably the air intake 12 has an air permeable screen (not shown) that prevents or restricts the influx of flying insects and other airborne debris such as leaves into the air intake without impeding the air flow. The apparatus 10 could be located on the inside of the gable end of the roof space 9 or on a platform built up from the ceiling rafters of the roof. It could be located anywhere where it can draw in ambient air.

The apparatus 10 has an electrically driven fan 16 that draws humid air in through an air intake 12 connected to one or more ventilated roof tiles 18 of the type shown schematically in FIG. 3 or FIG. 4, or a cowling 20 as shown in FIG. 5 and supplies the air to a water extractor 14. The Company Brett Martin Harcon PLC manufactures a range of ventilation tiles called “roofline range” that would be suitable for use as the ventilated tile 18 of the present invention. The Roofline RV8K and RV10K tiles are available with pipe terminals that normally, for ventilation purposes, would be connected to a soil pipe or to an extractor fan of a toilet or bathroom. In the present invention the pipe connectors are adapted to connect the RV8K or RV10K tile to the air inlet 12 of the water extractor 14 and operate in reverse to supply air to the water extractor 14.

The humid air drawn in through the tiles 18 and air intake 12 is cooled by a water extractor 14 to below its dew point to condense water from the air as described below, the water is collected in a chamber 20 and the air is exhausted outside of the roof space 9 through an exhaust pipe 22. The exhausted air may be expelled through a vent (not shown) in the gable end of the roof space 9 or out through further ventilator tiles (not shown) in the roof. Alternatively it may be possible to exhaust the air through vents into habitable rooms of the dwelling, although the primary purpose of this invention is to extract water rather than to condition the air as a part of an air conditioning system.

It may be possible to discharge the exhausted air into the roof space 9, but care needs to be exercised to ensure that the dried cold exhausted air does not cause build up of condensation in the roof space as the cooled exhausted air comes into contact with the humid air present in a ventilated roof space 9.

Ideally the air intake roof tile 18 is one that can be fitted from within the inside of the roof space 9 by removing an existing tile from the roof of the dwelling (shown in FIGS. 1 and 2 by the sloping line) and replacing it with the air intake tile 18.

In an alternative embodiment of the invention, the air intake tile may be a ridge tile 18 of the type shown in FIG. 4, but this is slightly more difficult to retro-fit to an existing roof from inside the roof space 9 and will require access to the outside of the roof to fit it.

In yet a further embodiment of the invention the air intake 12 may be connected to a cowling 20 of the type shown schematically in FIG. 5 that is mounted on a fixed stack pipe 22 connected to the air intake 12 and is rotatable on the fixed pipe 22 by means of an electric motor 32 Preferably the motor 32 is controlled by a servo 33 connected to a weather cock vane 25 so that the opening 26 of the cowl 20 faces into the wind. In yet a further embodiment the cowl 20 may be installed in a disused chimney.

The water extractor 14 has an electrically driven fan 16 that draws humid air in through the air intake 12 and condenses water from the atmospheric air. The extracted water is collected in at least one chamber 20 such as a sump that is an integral part of the water extractor 14. Condensed water from the chamber 20 is supplied through a first pipe 29 to a water tank 30 in the roof space 9 of the dwelling.

A float switch 31, or another type of liquid level detector, is provided in the tank 30 to control the electrical motor that drives the fan 16 of the water extractor 14 and thereby switch off the motor when the tank 30 is at a predetermined level. The water tank 30 is of conventional design in that it has a ball cock controlled inlet valve 31 that opens to let water into the tank 30 from the domestic water supply when the water level in tank 30 is low, and an outlet pipe 32 that supplies water to taps and other water devices such as cisterns or hot water tanks. The water inlet pipe 31 of the tank 30 is provided with an electrically controlled check valve 34 in the inlet supply pipe 35 from the mains water supply to enable the main water supply to be closed off when the water extractor 14 is operating. The check valve 34 is designed to fail in the open position so that the tank 30 can be filled from the mains water supply in the event of electrical failure or failure of the water extractor 14. In this case a float switch 36 is provided in tank 30 to control the operation of the water extractor 14 to top up tank 30.

An overflow pipe 38 is provided at the top of the tank 30 to allow water to overflow and be discharged outside of the dwelling if the tank 30 becomes overfilled and if desired can be captured in a water butt for garden or other use.

Referring to FIG. 1, the water extractor 14 is a dehumidifier of the type that uses a refrigerant, a compressor 40 to compress the refrigerant, a capillary tube 42 and an evaporative cooler 44 to cool the ambient humid air drawn by an electrically driven fan 16 in through an air intake 12 to below its dew point, and thereby condense water from the air. Either the exhaust air is vented to outside the roof space 9 or it could be supplied to air vents into one or more rooms of the dwelling, although the main purpose of the apparatus is to extract water, and not to condition the exhausted air.

The condensed water that is collected in the collection chamber 20 close to the evaporative cooler 44 is pumped by means of a pump 50 via the pipe 31 to the tank 30 to top up the tank 30. The level detector 36 in the tank 30 controls the operation of the compressor 40 of the water extractor 14 and the fan 16 so that they only run when the tank 30 needs to be topped up. In other words the fan 16 and the compressor 40 of the water extractor 14 is connected in an electrical circuit of so that it is only powered when the level of water in the tank 30 is below a predetermined level.

An example of a dehumidifier that may be suitable is that sold by Force 4 Chandlery under the model name XM Dehumidifier (product code: 830341). This model has a compressor driven from a power supply of 240 volts AC supply and will extract up to 250 ml of water a day from air above 15° C. having a relative humidity of 40% or more. It is compact, lightweight and CFC free. Fully automatic, it can be left for long periods of time as it has an automatic hot gas defrost function, so when temperatures go below 12° C. it will continue to work in cold temperatures. The unit has an integral 3.5 litre collection container 15 and it also has an external drain connection, allowing the unit to drain from the collection chamber 28 into a water tank in the roof of the dwelling. The unit weighs 14.5 Kg, measures 543 mm×250 mm×310 mm and has a moisture removal rate of 10 ltr/day (@30° C. and 80% relative humidity.

As shown in FIG. 2 the water extractor 14 could be more sophisticated than that shown in FIG. 1, in that it may be one that extracts purified water from atmospheric air. The water extractor 14 of FIG. 2 is similar to that shown in FIG. 1 and similar parts are given the same reference numbers. However, the water extractor 14 of FIG. 2 draws air through an air intake filter such as for example, an electrostatic filter 46 located in the air intake 12 leading from the ventilated tile 18 or the cowling 21, to remove most of the air borne particles in the air. The extracted water is collected in the collection chamber 20 and is passed under an Ultraviolet (UV) light source 48 in the chamber 28 where the water is irradiated with the UV rays that kill germs and bacteria in the collected water. The purified water is then pumped by a pump 50 through a second sediment screen 51 and through a filtration system 52 such as carbon blocks or Ultraviolet frequency filters. The water is then re-circulated through Ultraviolet rays or treated by ozone at an ozone treatment zone 54. The treated water is supplied to the water tank 18. It will be appreciated that the water extractor 14 shown in FIG. 3 has the advantage of reducing pathogens and bacteria that could otherwise accumulate in the tank 30.

An example of such an air to water extractor 14 that extracts drinkable water is that made by AIR2WATER GLOBAL Inc. under the model name Dolphin 1, which measures 1145 mm (height)×418 mm (width)×418 mm (depth) so would fit through a loft hatch opening of 514 mm×514 mm or one of 514 mm×704 mm. In it's present state this unit generates up to 22 litres of water a day from ambient air at 15° C. or above with a relative humidity of 35 to 95%. The Dolphin 1 machine first pulls air through an electrostatic filter, removing 93% of all air borne particles, then a condensation unit receives this clean humid airflow and condenses water vapour into liquid. As the machine collects the water, it drops into a collection tray and immediately passes into Ultraviolet (UV) light, where the water stays in contact with UV rays for approximately 30 minutes. This kills over 90% of all germs and bacteria in the water. The water is then pumped through a sediment screen and then through 2 solid block activated carbon (SBAC) 1 micron filters, which removes over 90% of any volatile organic chemicals that may be in the water. The water is then filtered through proprietary ultra-filtration (UF) membrane, with a pore size of 0.015 micron, to remove virtually all bacteria and common viruses. The water is then pumped into a reservoir tank and from the reservoir tank, the water is recycled every 30 minutes through the UV and back into the reservoir tank.

A further type of water extractor 14 that could be used is that which uses a thermoelectric Peltier cooling effect to cool a heat sink that is contacted by humid atmospheric air thereby to cool the air to below its dew point and condense water from the air. Although Peltier cooling devices may not be as efficient as, for example, an evaporative refrigeration system, they have the advantage of being light weight and relatively cheap. An example of such a Peltier type device that may be suitable is that made by sold by 4air.co.uk under the product name EF888 min-dehumidifier Prem-I-Air Brand. This machine will extract 600 ml/day (30° C. RH 80%), and has a 2-litre collection tank. The unit can be powered from a 240 volt AC 60 W 50Hz supply with a 12 volt 5 A DC adaptor.

A further type of known water extractor 14 that may be suitable for use in the present invention is the type known as a desiccant wheel which is dimensioned and arranged relative to an access opening in the ceiling of a dwelling so that it can be inserted into the roof space of the dwelling. This type of water extractor is shown schematically in FIG. 3 Referring to FIG. 6 there is shown a wheel 43 (there may be a bank of two or more such wheels (not shown)) that is water absorbent or hygroscopic. The, or each wheel 43 may be made from a porous, or air permeable substrate that is coated with, or contains silica gel. Other desiccant or hygroscopic materials may also be suitable. The, or each, wheel 43 is located co-axially in two discrete separate air flow channels 44, 45, with the plane of the disc of the, or each, wheel (43) lying normal to the flow of air through the channels 44, 45. The, or each, wheel 43 is positioned so that it lies normal to the air channels and is driven by a motor so that the one or more wheels (43) rotate.

Incoming moist air (shown by arrow (A) is caused to flow through a ventilated tile (shown schematically by the reference numeral 48) along one of the channels 44 by an electrically driven fan 29 and through the part of the one or more wheels 43 in the channel 44. Water within the air flow in channel 44 is absorbed by the desiccant or hygroscopic part of the, or each, wheel 43 that is exposed to the flow of incoming air. As the moistened wheel, or wheels 43 rotate, the moistened part of the wheel, or each wheel 43 is brought into the path of a second flow of air flowing in channel 45.

A second flow of air that is used to “dry” the one or more desiccant wheels is created either by recirculating the air flowing out of the channel 44 after it has given up the water to the one or more wheels (44), or by using a discrete second flow of air which may be drawn from inside the roof space or from outside the dwelling. A second fan may be provided to move the air along the channel 45).

The “drying air” is caused to flow through a first heat exchanger 46 which heats the air and then through the moistened bottom section of the, or each, wheel 43 to remove the water from the one or more wheels (43). The moisture in the second flow of air is extracted by cooling it to below the dew point of the air, by passing it through a second heat exchanger 47. The condensed water is collected in a sump 15 of the apparatus shown in FIGS. 1 to 3.

The exhausted air from channel 45 that leaves the heat exchanger 46 is dumped outside of the dwelling.

In an alternative embodiment of the invention the air intake tile may be a ridge tile 18 of the type shown in FIG. 3. In yet a further embodiment the air intake may be formed by a cowling 20 of the type shown in FIG. 5.

Whilst it may be possible to use solar panels to generate electrical power to drive the fan of the water extractor 14 it is thought that this would make the system far too expensive for most purposes. Furthermore, it may be possible to use wind driven turbines to generate electrical power to drive the fan of the water extractor. The wind turbine could be a vertical wind turbine that fits within the profile of a normal chimney. One such turbine is that called a

“Secret Energy Turbine” as sold by Smart Power Products Limited. Another turbine is that invented by the Australian inventor Graeme Attey and called a “drum turbine”. This roof-top wind turbine is small, cheap, quiet and sits at the peak of the roof-line in order to capture wind at it's maximum speed. It is thought that in many densely populated areas such turbines would be unsightly and add significantly to noise pollution and the cost.

The pipes may be rigid or flexible pipes, although preferably the hoses are thin flexible hoses. An advantage of this type of hose is that they can be bent to fit around obstacles in the roof space 9. Furthermore, this gives more flexibility in where the other components such as the pumps can be disposed within the roof space. The hoses may be connected to the other components of the apparatus my any means known in the art, which means may be temporary or permanent.

In the above described embodiments the water extractor 14 has an electrically driven fan. This is preferred, because it is relatively easy to retrofit the water extractor to an existing dwelling. Furthermore the water extractor is connected in an electrical circuit that only operates when the tank 30 needs to be topped up. It is to be understood that the water extractor may be provided with its own rechargeable battery, such as for example a Lithium Ion Polymer battery (LiPo battery) so that the water extractor can run even when the main power supply to the dwelling is interrupted. It may be possible to provide a solar powered generator to recharge the battery, although this may not be very practical for some high powered LiPo batteries that require a significant power charge beyond the present capabilities of reasonable sized solar power generators.

Where the dwelling does not have an accessible roof space, the water separator 14 may be installed at any convenient location providing that the air intake is located where it can draw humid air into the water separator.

It is to be understood that a control panel with visible and/or audible warning devices may be locate at an accessible region within the dwelling so that occupants of the dwelling can monitor or control the operation of the water separator without the need to enter the roof space of the dwelling.

It is to be understood that the air intake and/or the ventilated tile may be shaped, or have vanes (not shown), so that in use air flowing into the ventilated tile and air intake is funnelled to increase the velocity of the air flowing into the water extractor.

Although the above description refers to installation in a dwelling such as a house or bungalow, it is to be understood that the invention may be adapted for use in mobile or static caravan, or trailer home, providing that the water separator is suitably dimensioned.

The water recycling system of the present invention may be combined with, or incorporated into, a rain water collection and recycling system and the recycled rainwater fed into the same tank 30 as the present invention. 

1-19. (canceled)
 20. Apparatus for extracting water from the atmosphere and supplying the extracted water to an existing domestic water supply of a dwelling that has a mains water filled tank, said apparatus comprising an air intake located to receive humid air from outside the dwelling, a cooling means for condensing water out of the air, a fan operable to draw air in through the air intake and pass the air over the cooling means, and collection means for collecting the condensed water and supplying the collected water to the water supply tank of the dwelling to replenish water in the tank.
 21. Apparatus according to claim 20 wherein the collection means comprises a water collection chamber and a pump is provided for pumping condensed water from the collection chamber to the water tank.
 22. Apparatus according to claim 20 wherein the apparatus is dimensioned and arranged relative to an access opening that leads from the dwelling into a roof space of the dwelling to be small enough to pass through the opening and be located in the roof space, and the collection means comprises a water collection chamber and a pump means operable to pump the collected water to a mains water filled tank located the roof space of the dwelling.
 23. Apparatus according to claim 20 wherein the air intake is connected to a ventilated tile of the roof.
 24. Apparatus extractor according to claim 20 wherein the cooling means is a dehumidifier of the type that uses a refrigerant, a compressor to compress the refrigerant and an evaporative cooler to cool the air flowing in contact with the cooler to below its dew point, and thereby condense water from the air.
 25. Apparatus according to claim 20 wherein the cooling means is a dehumidifier of the type that uses a thermoelectric Peltier device that cools a heat sink that is used to cool the air that contacts the heat sink to below its dew point to condense water from the air.
 26. Apparatus according to claim 23 wherein the roof tile is connected to the air intake of the water extractor by means of a pipe connector.
 27. Apparatus according to claim 20 wherein the fan is driven by an electrically powered motor.
 28. Apparatus according to claim 1 wherein the fan is driven by a wind driven turbine.
 29. Apparatus according to claim 20 wherein a level detector is provided in the collection means that is operable to control the operation of the water extractor so that the water extractor only runs when the tank needs to be topped up.
 30. Apparatus according to claim 20 wherein the air intake has an air filter to remove air-borne particles in the air.
 31. Apparatus according to claim 30 wherein the filter is an electrostatic filter.
 32. Apparatus according to claim 20 wherein an ultraviolet light source is provided for irradiating the condensed water to purify the water.
 33. Apparatus according to claim 20 wherein a filtration system is provided through which the condensed water flows.
 34. Apparatus according to claim 33 wherein a sediment screen is provided for filtering the condensed water.
 35. Apparatus according to claim 33 wherein the filtration system includes porous carbon blocks through which the water flows.
 36. Apparatus according to claim 33 wherein the collected water is subjected to an ozone treatment to produce drinkable water that is available for occupants of the dwelling. 